Pulp process



A. HQCHE Oct. 27, 1936.

PULP PROCES S Original Filed Nov. 20, 1954 5. w ATTORNE Patented Oct. 27, 1936 UNITED STATES- PULP PROCESS Adam Hoche, Brooklyn, N. Y.

Application November 20, 1934, Serial No. 753,799

, Renewed March 18, 1936 2 Claims. (01. 92-9) This invention relates to cellulose fibres, particularly to the separation thereof from bodies consisting largely thereof associated with undesired natural substances.

Those skilled in the art of making cellulose pulp, that is, the separation of cellulose fibres from bodies consisting largely thereof associated with undesired or deleterious substances, are fully aware that the present day processes includemany steps, which require costly equipment, are slow in operation, and, due to the necessary agitation of the fibre and the subjection thereof to powerful chemical substances for protracted periods, result in a pulp or fibre which is both short and weak. A further disadvantage with present processes is the low yield.

Applicant, realizing the deficiencies in. present day processes, after protracted study, experimentation, analysis and testing arrived at the conclusion that a proper process for the recovery of cellulose fibres, must be one in which the fibre is subjected to the least possible mechanical agitation or handling; to the lowest possible temperature; treated for the shortest possible time; subjected to a chemical substance or substance most active in action upon the foreign or deleterious or undesiredsubstances associated with the fibre, and least active or injurious to the fibre itself; and, further, that the process should preferably be such that the number of steps is re-;

duced to a minimum, preferably substantially one, to the end that separation and bleaching be accomplished in one treatment.

With this end in view, applicant has devised a process for the separation of cellulose fibre from associated undesired natural substances which is, in effect, a one step process. This process is carried out without mechanical agitation; at room temperature, save for any increased temperature due to the reacting masses; necessitates an extremely short exposure of the fibre to the chemicals used; includes the use of chemicals which are extremely active toward the undesired and deleterious substances and comparatively inert, in the concentrations used, toward the cellulose; and substantially separates the deleterious substances and bleaches in one treatment, which completes the process save for a I necessary separation of the chemicals used from the treated material and a subsequent water wash of the material to remove the last traces of chemicals and soluble impurities from the cellulose pulp.

In order to better describe the new process applicant has selected a specific form of apparatus merely to illustrate the carrying out of the process.

In describing the invention in detail and the particular form of apparatus selected to illustrate the invention reference is had to the accompanying drawing in which like characters of ref- .erence designate like parts throughout the several views, and in which:

Figure 1 is a side elevational view with some parts broken away to more clearly show the construction, of an apparatus by which applicants process may be carried out; Fig. 2 is a top plan view of the apparatus as shown in Fig. 1.

In carrying out the process, applicant selects a suitable cellulose fibre carrying mass, such as wood chips, sisal, hemp, bagasse or the like, in fact any of the ordinary and well known source materials.

The selected material is placed in a vessel of suitable form, size and material and equipped with the obvious accessories for facilitating the treatment. In general, any vessel of the general form of a tank is suitable. The material is preferably placed somewhat loosely in the tank, to the end that the treating solution may readily penetrate to every particle.

Onto the material in the selected vessel, applicant flows or otherwise suitably distributes the treating solution so that the material is completely saturated or covered.

30 In the drawing applicant has illustrated a preferred form of vessel for containing the material to be treated. In the figures, numerals I, 2, 3, 4 and 5 designate containing vessels. These containing vessels should be made of an acid resisting material and one which is also resistant to chlorine and sulphur dioxide fibres or fumes. A glass vessel is preferred.

Into each of the vessels I to 5 inclusive there is placed a fibre containing mass, such as wood chips, up to the level 6. In addition to the fibre bearing mass, each vessel receives a quantity of dilute sulphuric acid sufficient to saturate the material and go up to a level just a little above the material, that is, to the level 1. The dilute sulphuric acid solution should be of a concentration from about 1% to about 10% sulphuric acid.

Each of the vessels I to 5 inclusive is fitted with a stopper, as 8, formed with two orifices therein.

The orifices in the stopper 8 receive the tubes 9 l and Ill. These tubes 9 and [0 are preferably made of material resistant to the chemicals with which they are to come in contact and are preferably made of glass. The tube 9 extends nearly to the bottom of the vessel I, while the tube Ill extends only a short distance below the bottom of the stopper 8. Each of the vessels is equipped with tubes 9 and III. The tube III of one vessel is connected to the tube 9 or the succeeding vessel by means of any suitable and appropriate connection as by the flexible tube II, formed of any suitable chemical resisting material, such as caoutchouc or rubber.

The material in the vessels I to inclusive is subjected to the action of a gas which is formed in the vessel l2. This vessel I2 contains a suitable quantity of acetic anhydride. In the illustration acetic anhydride is shown as going to the level of line I3. The vessel I2 is fitted with a stopper I 3' which is provided with orifices for three tubes, I, I5 and IS. The tube I4 terminates lust shortly below the lower level of the stopper I3. The tubes I5 and I6 extend down to a point a short distance from the bottom of the vessel I2 so that they are well below the top level of the liquid acetic anhydride.

The tube I5 is connected with a cylinder II of sulphur dioxide, that is. the well known sulphur dioxide tank of commerce in which the sulphur dioxide is in the liquid form, although, of course, it is to be understood that any appropriate means could be selected to supply the sulphur dioxide to the tube I5.

The tube It is connected to a tank I! of chlorine. This is the ordinary and well known chlorine tank of commerce and it is to be understood that any other suitable and appropriate means for supplying chlorine gas to tube I6 may be used.

By means of valves as I9, or any other suitable means, the gaseous chlorine and sulphur dioxide are allowed to bubble through the acetic anhydride in the vessel I2. The gaseous chlorine and gaseous sulphur dioxide in the presence of acetic anhydride probably unite and form sulphuryl chloride which, as a gas, passes into tube I4 and through the connecting tube to tube 9 and issuing at the lower end of the tube 9 beneath the surface oi the dilute sulphuric acid bubbles through the liquid and if unoonsumed arises from the surface of the liquid and continues its course through tubes Ill, I I and 9 to vessel 2 and repeats its cycle through the remaining vessels. It is, of course, to be understood that a sufllcient number of vessels as I are arranged in tandem so that no loss of the sulphuryl chloride will occur,'so that, no unused sulphuryl chloride will issue from the short tube III of vessel 5. e

In carrying out the process the acetic anhydride, in general, may be at room temperature, but if found desirable it may be warmed slightly in order to increase its catalytic action of causenough acetic anhydride also goes over to act as a catalyst so as to cause those gases to com-' bine so there is no loss.

The process is carried on until the material in vessel I has reached a stage of completion which is determined by the ordinary and usual tests. After the material has been completely acted upon, it is then treated in any mitable manner to remove the acid liquor from the fibre. This is perhaps best done by the use of a centrifuge. After all of the liquids are separated from the solid matter, a water wash is then given, preferably in the centrifuge, until the fibre mass is substantially acid free.

Upon the removal of vessel I, vessel 2 is inserted in its place and 3 in place of 2 and so on, adding one more vessel to the tandem after vessel 5. By this manner of working every particle of sulphuryl chloride that is formed has a chance to do useful work.

The product resulting from this process is usually of a color such that no bleaching is necessary but if bleaching is necessary it may be applied in the usual manner.

As no heating or cooking of the fibre mass is necessary, and no beating or agitation thereof is required, the fibre is in excellent condition and is very strong.

The yield of fibre according to this process is perhaps 15% to 20% higher than usual processes. The product resulting from this process is especially good for bond and writing papers.

Having described the principle and mode of operation of my invention and a particular-application thereof and a specific apparatus by which myprocess may be carried out, I desire to have it understood that the specific apparatus selected is merely illustrative and does not exhaust the possible apparatus forms by which the underlying principles of my invention may be exemplified.

What I claim as new and desire to secure by Letters Patent oi the United States is:

1. A process of separating cellulose fibre from a fibre mass admixed with undesired other natural substances and simultaneously bleaching it which consists in thoroughly saturating the said mass with a water solution of sulphuric acid of a concentration from 1% to 10% sulphuric acid, and then exposing the mass to the action of the product formed by bubbling chlorine gas and sulphur dioxide gas through acetic anhydride, then removing adhering liquid and water washing until substantially acid free.

2. A process of separating cellulose fibre from a fibre mass admixed with undesired other natural substances and simultaneously bleaching it which consists in thoroughly saturating the said mass with a water solution of sulphuric'acid of a concentration from 1% to 10% sulphuric acid, and then exposing the mass for from one to five hours to the action of the product formed by bubbling chlorine gas and sulphur dioxide gas through acetic anhydride, then removing adher-' ing liquid and water washing until substantially acid free.

' ADAM HOCHE. 

